The born-again ejecta adds up to the planetary nebula shell and does not play a prominent additional role at late times. The born-again ejecta can lead to an early flux excess of the SN Ia only if the SN ejecta collides with the born-again ejecta in the first few days, before the SN Ia becomes bright by radioactive decay.
The process is like the early flux excess that might result from the collision of the SN Ia ejecta with the circumstellar matter in some other SN Ia scenarios (e.g., [1]}, [2]}, [3]}, [4]}).
